The acronym RDF stands for Resource Description Framework. It's an extremely simple format, which allows the computer to manipulate it. However, it is highly structured. So it is painstaking for a person to write and read it.
In Canada, there are several data sets in CSV format, which Mr. Stirling referred to. These are Excel spreadsheets recorded line by line, with commas between columns. Producing this type of data in CSV format is quite easy. There are no technological barriers. You just have to develop the corporate culture.
Some types of data do not lend themselves to this, such as significant quantities of geographic maps or information on geographic maps. The interest in this data lies in the graphic/visual aspect. You are obviously not going to capture that in an Excel spreadsheet. In that sense, there's a limit to the information that can be disseminated.
However, CSV formats can be readily manipulated by computer and can be converted into RDF format. Some governments have outright decided to put everything in RDF format. In the United States, as in the United Kingdom, there's a desire to go the way of RDF.
As I explained, the barriers stem from the fact that the nature of the data does not lend itself to this format in some cases. The alternative would be to set up automatic conversion systems for certain types of data.